JP2008153704A - Heat dissipation structure - Google Patents

Heat dissipation structure Download PDF

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JP2008153704A
JP2008153704A JP2008062246A JP2008062246A JP2008153704A JP 2008153704 A JP2008153704 A JP 2008153704A JP 2008062246 A JP2008062246 A JP 2008062246A JP 2008062246 A JP2008062246 A JP 2008062246A JP 2008153704 A JP2008153704 A JP 2008153704A
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heat
transfer sheet
heat transfer
heating element
bulk density
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JP5114255B2 (en
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Yoshiaki Hirose
芳明 広瀬
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Toyo Tanso Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • C01B32/22—Intercalation
    • C01B32/225—Expansion; Exfoliation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73251—Location after the connecting process on different surfaces
    • H01L2224/73253—Bump and layer connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01004—Beryllium [Be]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01012—Magnesium [Mg]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01019—Potassium [K]

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  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipation structure which can reduce thermal resistance from a heating element to a heat sink although the heat dissipation structurebeing is attached with a small pressing force. <P>SOLUTION: A heat dissipation structure 10 which is mounted on a heating element H and dissipates heat of the heating element H, includes a heat sink 12; a heat transfer sheet 11 made from expanded graphite, which heat transfer sheet is arranged between the heat sink 12 and the heating element H; and a resin film 13 arranged at least either between the heat transfer sheet 11 and the heating H or between the heat transfer sheet 11 and the heat sink 12. The heat transfer sheet 11 made from expanded graphite is adopted, which can reduce thermal resistance from the heating element H to the heat sink 12, thereby improving effect of cooling the heating element H. In addition, the resin film 13 can prevents, for example, expanded graphite leaving the heat transfer sheet 11 from dispersing around the heat transfer sheet 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、放熱構造体に関する。コンピュータに使用されるＣＰＵ等の発熱体の冷却には、ヒートシンク等の放熱体が使用されるが、発熱体と放熱体との密着性が悪い場合には、両者間でも熱伝導が悪くなり、冷却性能の低下につながる。かかる冷却性能の低下を防ぐために、熱伝導性を有しかつ発熱体と放熱体との間には両者の間の密着性を高めることができるシートが配設される。
本発明は、かかる発熱体とヒートシンク等の放熱体との間に挟んで使用される伝熱シートを備えた放熱構造体に関する。 The present invention relates to a heat dissipation structure . A heat sink such as a heat sink is used for cooling a heat generating element such as a CPU used in a computer. However, when the adhesion between the heat generating element and the heat dissipating element is poor, the heat conduction between the two becomes poor. This leads to a decrease in cooling performance. In order to prevent such a decrease in cooling performance, a sheet having thermal conductivity and capable of enhancing the adhesion between the heating element and the radiator is disposed.
The present invention relates to a heat radiating structure including a heat transfer sheet that is used by being sandwiched between such a heat generating body and a heat radiating body such as a heat sink.

発熱体とヒートシンクとの間に挟んで使用するシートとして、グラファイトシートが使用されている。このグラファイトシートは、発熱体とヒートシンクとの間に配設され、発熱体とヒートシンクによって挟んで加圧された状態で取り付けられる。すると、発熱体やヒートシンクの表面に存在する凹凸がグラファイトシートに食い込み、発熱体とグラファイトシートの間、および、グラファイトシートとヒートシンクの間に隙間ができないようにすることができるから、接触部分の熱抵抗が小さくすることができ、冷却効率を向上させることができる。   A graphite sheet is used as a sheet used by being sandwiched between a heating element and a heat sink. The graphite sheet is disposed between the heating element and the heat sink, and is attached in a state of being pressed between the heating element and the heat sink. Then, the unevenness existing on the surface of the heating element and the heat sink bites into the graphite sheet, so that there is no gap between the heating element and the graphite sheet and between the graphite sheet and the heat sink. The resistance can be reduced, and the cooling efficiency can be improved.

発熱体とヒートシンクによってグラファイトシートを挟む力は、ヒートシンクを発熱体に取り付ける力に依存するが、ＣＰＵに大きな応力をかけると内部チップが変形することから、ヒートシンクを発熱体に取り付ける力は低下しており、従来、５ＭＰａ程度であったものが、一部では２ＭＰａ程度まで低下している。ヒートシンクを発熱体に取り付ける力が低下すると、発熱体やヒートシンクの表面に存在する凹凸がグラファイトシートに十分に食い込むことができなくなるため、発熱体およびヒートシンクとグラファイトシートの間に空隙が多数残された状態で取り付けられてしまい、熱抵抗が大きくなり、冷却効率が低下するという問題が生じる。   The force to sandwich the graphite sheet between the heating element and the heat sink depends on the force to attach the heat sink to the heating element. However, if a large stress is applied to the CPU, the internal chip will be deformed. In addition, what was conventionally about 5 MPa is partially reduced to about 2 MPa. When the power to attach the heat sink to the heating element is reduced, the unevenness existing on the surface of the heating element and the heat sink cannot sufficiently penetrate into the graphite sheet, leaving many gaps between the heating element and the heat sink and the graphite sheet. It is attached in a state, resulting in a problem that the thermal resistance is increased and the cooling efficiency is lowered.

かかる問題を解決するために、常温で液体であり、かつ使用温度範囲において相変化がない物質と、グラファイトシートを備えた熱伝導性シートが開発されている（特許文献１）。この熱伝導性シートでは、グラファイトシート中に存在する液体が自由に移動できるため、取り付け時の加圧力が小さくても、微細な凹凸にはグラファイトシートを配置させることができ、５〜100μｍといった比較的大きな窪み部分には加圧力で移動した液体が溜めることができるとの記載がある。そして、熱伝導性シートと発熱体およびヒートシンクとの間に空隙が形成されることを防ぐことができるから、熱抵抗を最小限に抑えることにより良好な熱伝達が得られるという効果を奏すると記載されている。   In order to solve this problem, a thermally conductive sheet including a graphite sheet and a substance that is liquid at room temperature and has no phase change in the operating temperature range has been developed (Patent Document 1). In this thermally conductive sheet, the liquid present in the graphite sheet can move freely, so even if the applied pressure at the time of attachment is small, the graphite sheet can be placed on fine irregularities, and a comparison of 5 to 100 μm is possible. There is a description that the liquid moved by the applied pressure can be stored in the large depression. And since it is possible to prevent the formation of a gap between the heat conductive sheet, the heating element and the heat sink, it is described that there is an effect that good heat transfer can be obtained by minimizing the thermal resistance. Has been.

しかるに、上記熱伝導性シートでは、グラファイトシート中に液体物質が存在することにより、発熱体とヒートシンクとの間に挟み込んだときにおけるシートの圧縮性、言い換えれば、グラファイトシートと発熱体等との密着性の向上が妨げられるため、熱伝導性シートの熱抵抗をそれほど小さくできない。
また、グラファイトシートに液体物質を含浸させるための工程が余分にかかってしまうため、生産性が悪くコストが高くなるし、また液体物質の劣化や、液体物質がグラファイトシートから放出されることにより、周辺装置の汚染の問題も生じる。 However, in the above heat conductive sheet, due to the presence of a liquid substance in the graphite sheet, the compressibility of the sheet when sandwiched between the heating element and the heat sink, in other words, the adhesion between the graphite sheet and the heating element, etc. Therefore, the thermal resistance of the heat conductive sheet cannot be reduced so much.
In addition, since an extra step for impregnating the graphite sheet with the liquid material is required, the productivity is low and the cost is high, and the deterioration of the liquid material and the release of the liquid material from the graphite sheet There is also a problem of contamination of peripheral devices.

特開２００４−３６３４３２号JP 2004-363432 A

本発明は上記事情に鑑み、小さい取り付け圧力でも、発熱体から放熱体までの熱抵抗を小さくすることができる放熱構造体を提供することを目的とする。 An object of this invention is to provide the thermal radiation structure which can make small the thermal resistance from a heat generating body to a thermal radiation body even with a small attachment pressure in view of the said situation.

第１発明の放熱構造体は、発熱体に取り付けられ、該発熱体の熱を放熱する放熱構造体であって、放熱体と、該放熱体と前記発熱体との間に配設される膨張黒鉛を素材とする伝熱シートと、該伝熱シートと前記発熱体との間、もしくは該伝熱シートと前記放熱体との間の、すくなくとも一方に配設される樹脂フィルムとからなることを特徴とする。
第２発明の放熱構造体は、第１発明において、前記樹脂フィルムは、ポリエチレンテレフタラートであることを特徴とする。
第３発明の放熱構造体は、第１または第２発明において、前記樹脂フィルムが、前記伝熱シートに取り付けられていることを特徴とする。
第４発明の放熱構造体は、第１、第２または第３発明において、前記伝熱シートは、かさ密度が、0.8Ｍｇ／ｍ３より小さいことを特徴とする。
第５発明の放熱構造体は、第１、第２、第３または第４発明において、前記伝熱シートは、厚さ方向から34.3ＭＰａの加圧力で加圧圧縮したときにおいて、圧縮率が５０％以上であり、かつ復元率が５％以上であることを特徴とする。 A heat dissipating structure of the first invention is a heat dissipating structure that is attached to a heat generating element and dissipates heat from the heat generating element, and is disposed between the heat dissipating element and the heat dissipating element and the heat generating element. It consists of a heat transfer sheet made of graphite and a resin film disposed at least on one side between the heat transfer sheet and the heating element, or between the heat transfer sheet and the heat dissipation element. Features.
The heat dissipation structure of the second invention is characterized in that, in the first invention, the resin film is polyethylene terephthalate.
The heat dissipation structure of the third invention is characterized in that, in the first or second invention, the resin film is attached to the heat transfer sheet.
According to a fourth aspect of the present invention, in the first, second or third aspect, the heat transfer sheet has a bulk density of less than 0.8 Mg / m 3 .
A heat dissipation structure according to a fifth aspect of the present invention is the first, second, third or fourth aspect of the present invention, wherein the heat transfer sheet has a compression ratio of 50 when compressed and compressed with a pressure of 34.3 MPa from the thickness direction. %, And the restoration rate is 5% or more.

第１発明によれば、膨張黒鉛を素材とする伝熱シートを採用しているので、発熱体から放熱体までの熱抵抗を小さくすることができ、発熱体を冷却する効果を高くすることができる。しかも、樹脂フィルムによって伝熱シートから離脱した膨張黒鉛等が伝熱シートの周囲に飛散したりすることを防ぐことができる。
第２発明によれば、厚さ方向の熱伝導率を伝熱シートと同程度とすることができる。
第３発明によれば、伝熱シートおよび樹脂フィルムを、発熱体と放熱体との間に配置することが容易になる。
第４発明によれば、伝熱シートのかさ密度が低いので、発熱体と放熱体との間に挟んで加圧すれば、加圧力が小さくても容易に圧縮され、両者との密着性が高くなる。よって、発熱体から放熱体までの熱抵抗が小さくなるから、発熱体を冷却する効果を高くすることができる。
第５発明によれば、伝熱シートが高い圧縮復元性を有することから、複数回使用しても、かさ密度を所定の密度以下に保っておくことができ発熱体や放熱体との密着性を高く保っておくことができる。よって、複数回使用しても熱抵抗を小さく保っておくことができるから、伝熱シートの再利用性を向上させることができる。そして、伝熱シートを再利用することができるので、省資源化に寄与することができる。 According to the first invention, since the heat transfer sheet made of expanded graphite is employed, the thermal resistance from the heating element to the heat radiating body can be reduced, and the effect of cooling the heating element can be increased. it can. Moreover, it is possible to prevent the expanded graphite or the like detached from the heat transfer sheet by the resin film from being scattered around the heat transfer sheet.
According to the second invention, the thermal conductivity in the thickness direction can be made comparable to that of the heat transfer sheet.
According to the 3rd invention, it becomes easy to arrange | position a heat-transfer sheet and a resin film between a heat generating body and a heat radiator.
According to the fourth invention, since the bulk density of the heat transfer sheet is low, if it is sandwiched between the heat generating element and the heat radiating member and pressed, it is easily compressed even if the applied pressure is small, and the adhesiveness between the two is improved. Get higher. Therefore, since the thermal resistance from the heat generating element to the heat radiating element is reduced, the effect of cooling the heat generating element can be enhanced.
According to the fifth invention, since the heat transfer sheet has a high compression recovery property, the bulk density can be kept below a predetermined density even when used multiple times, and the adhesion to the heating element and the heat dissipation element Can be kept high. Therefore, since the thermal resistance can be kept small even when used multiple times, the reusability of the heat transfer sheet can be improved. Then, it is possible to reuse the heat transfer sheet, it is possible to contribute to resource saving.

つぎに、本発明の実施形態を図面に基づき説明する。
本発明の放熱構造体は、コンピュータのＣＰＵや携帯電話の基板、ＤＶＤレコーダーやサーバーなどの発熱体を冷却するために使用されるものであり、放熱体１２と、放熱体１２と発熱体Ｈとの間に配設される伝熱シート１１および樹脂フィルム１３とから構成されている。 Next, an embodiment of the present invention will be described with reference to the drawings.
The heat dissipating structure of the present invention is used to cool a heat generating body such as a CPU of a computer, a substrate of a mobile phone, a DVD recorder or a server, and includes a heat dissipating body 12, a heat dissipating body 12, and a heat generating body H. It is comprised from the heat-transfer sheet | seat 11 and the resin film 13 which are arrange | positioned between.

まず、放熱体１２について説明する。  First, the heat radiator 12 will be described.
放熱体１２は、例えば、ヒートシンクなどであり、後述する伝熱シート１１や樹脂フィルム１３の熱を吸収し、輻射や対流、熱伝導等によって気体や液体、他の部材等に対して、供給された熱を放出するものである。The radiator 12 is, for example, a heat sink, and absorbs heat from a heat transfer sheet 11 and a resin film 13 to be described later, and is supplied to gas, liquid, other members, etc. by radiation, convection, heat conduction, or the like. The heat is released.
なお、この放熱体１２は、上記のごとき供給された熱を放出する放熱機能を備えているものだけでなく、伝熱シート１１や樹脂フィルム１３の熱を吸収する吸熱機能も備えているもの、および、放熱機能と吸熱機能を両方備えているものでもよい。つまり、伝熱シート１１や樹脂フィルム１３の熱を外部に放出する機能を有しているものであればよい。  The radiator 12 has not only a heat dissipation function that releases the heat supplied as described above, but also a heat absorption function that absorbs heat of the heat transfer sheet 11 and the resin film 13, And what has both a thermal radiation function and a thermal absorption function may be sufficient. That is, what is necessary is just to have the function to discharge | release the heat | fever of the heat-transfer sheet 11 and the resin film 13 outside.

つぎに、伝熱シート１１について説明する。
伝熱シート１１は、天然黒鉛やキャッシュ黒鉛等を硫酸や硝酸等の液体に浸漬させた後、400℃以上で熱処理を行うことによって形成された膨張黒鉛をシート状に形成したものであり、その厚さが0.05〜5.0ｍｍ、かさ密度が1.0Ｍｇ/ｍ３よりも小さくなるように形成されたものである。
膨張黒鉛は、芋虫状または繊維状をしたもの、つまり、その軸方向の長さが半径方向の長さよりも長いものであり、例えば、その軸方向の長さが１ｍｍ程度、かつ、半径方向の長さが300μｍ程度のものである。そして、伝熱シート内部では、上記のごとき膨張黒鉛同士が絡みあっているのである。 Next, the heat transfer sheet 11 will be described.
The heat transfer sheet 11 is a sheet of expanded graphite formed by immersing natural graphite or cash graphite in a liquid such as sulfuric acid or nitric acid and then performing a heat treatment at 400 ° C. or higher. It is formed so that the thickness is 0.05 to 5.0 mm and the bulk density is smaller than 1.0 Mg / m 3 .
Expanded graphite is worm-like or fibrous, that is, its axial length is longer than its radial length. For example, its axial length is about 1 mm and its radial length is about 1 mm. Is about 300 μm. Then, in the internal heat transfer sheet is of expanded graphite between the such as are entangled.

なお、伝熱シート１１は上記のごとき膨張黒鉛だけで形成してもよいが、フェノール樹脂やゴム成分等のバインダーが若干（例えば５％程度）の混合されていてもよい。
さらになお、上記のごとき膨張黒鉛から伝熱シート１１を形成する方法は、とくに限定されない。 The heat transfer sheet 11 may be formed only from expanded graphite as described above, but a slight amount (for example, about 5%) of a binder such as a phenol resin or a rubber component may be mixed.
Still further, a method of forming a such expanded graphite or RaDennetsu sheet 11 described above is not particularly limited.

ここで、上記のごとき膨張黒鉛から形成されたシート（膨張黒鉛シート）は、かさ密度の増加とともに面方向の熱伝導率は向上する一方、柔軟性は低下する。このため、膨張黒鉛シートは、その用途に応じてそのかさ密度が調整され、通常、伝熱シートとして使用するものは熱伝導性を重視しかさ密度が高くなる（例えば、1.3Ｍｇ/ｍ３以上）ように構成するのに対し、壁等の断熱材や電磁波遮蔽材として使用するものはかさ密度が低くなる（例えば、1.0Ｍｇ/ｍ３以下）ように構成される。
本発明の放熱構造体１０に使用する伝熱シート１１は、熱伝導性よりも柔軟性を重視して構成されたものであり、通常、断熱材や電磁波遮蔽材として使用される、1.0Ｍｇ／ｍ３よりかさ密度の小さい膨張黒鉛シートであることに特徴がある。そして、かさ密度が1.0Ｍｇ／ｍ３以上の膨張黒鉛シートは柔軟性が低下し発熱体と放熱体との密着性が悪くなるのであるが、かさ密度を1.0Ｍｇ／ｍ３より小さくしたことによって、後述するように、発熱体や放熱体との密着性が向上するのである。とくに、かさ密度を0.9Ｍｇ／ｍ３以下とすることが好ましいが、その理由は後述する。 Here, the sheet (expanded graphite sheet) formed from expanded graphite as described above has improved thermal conductivity in the surface direction with an increase in bulk density, while lowering flexibility. For this reason, the expanded graphite sheet has its bulk density adjusted according to its use, and those used as a heat transfer sheet usually have a high bulk density with an emphasis on thermal conductivity (eg, 1.3 Mg / m 3 or more). In contrast, a material used as a heat insulating material such as a wall or an electromagnetic wave shielding material is configured to have a low bulk density (for example, 1.0 Mg / m 3 or less).
The heat transfer sheet 11 used in the heat dissipation structure 10 of the present invention is configured with emphasis on flexibility rather than thermal conductivity, and is generally used as a heat insulating material or an electromagnetic shielding material, 1.0 Mg / It is characterized by an expanded graphite sheet having a bulk density smaller than m 3 . And an expanded graphite sheet having a bulk density of 1.0 Mg / m 3 or more has reduced flexibility and poor adhesion between the heating element and the heat radiating body. However, the bulk density was made smaller than 1.0 Mg / m 3 . As will be described later, the adhesion to the heat generator and the heat radiator is improved. In particular, the bulk density is preferably 0.9 Mg / m 3 or less, and the reason will be described later.

つぎに、樹脂フィルム１３について説明する。  Next, the resin film 13 will be described.
樹脂フィルム１３は、伝熱シート１１と発熱体Ｈとの間、または、伝熱シート１１と放熱体１２との間に配置されるものである。この樹脂フィルム１３は、厚さ方向の熱伝導率が伝熱シート１１と同程度であり、100℃程度の耐熱性を有している素材からなるフィルム、例えば、ポリエチレンテレフタラート等を素材をするフィルムである。  The resin film 13 is disposed between the heat transfer sheet 11 and the heat generator H or between the heat transfer sheet 11 and the heat radiator 12. This resin film 13 is made of a film made of a material having a heat conductivity in the thickness direction similar to that of the heat transfer sheet 11 and having a heat resistance of about 100 ° C., such as polyethylene terephthalate. It is a film.
この樹脂フィルム１３を設ければ、伝熱シート１１から離脱した膨張黒鉛等が伝熱シート１１の周囲に飛散したりすることを防ぐことができる。  If the resin film 13 is provided, it is possible to prevent the expanded graphite and the like detached from the heat transfer sheet 11 from being scattered around the heat transfer sheet 11.
なお、図１では樹脂フィルム１３は、伝熱シート１１と発熱体Ｈとの間に設けられているが、伝熱シート１１と放熱体１２との間に設けてもよいし、伝熱シート１１と発熱体Ｈとの間および伝熱シート１１と放熱体１２との間の両方の間に設けてもよい。  In FIG. 1, the resin film 13 is provided between the heat transfer sheet 11 and the heat generator H, but may be provided between the heat transfer sheet 11 and the heat radiator 12, or the heat transfer sheet 11. And between the heat generating body H and between the heat transfer sheet 11 and the heat radiating body 12.

つぎに、本発明の放熱構造体１０の使用方法を説明する。
図１（Ａ）は本発明の放熱構造体１０の使用状態の一例を示した図であり、（Ｂ）は実施例において本発明の放熱構造体に使用する伝熱シートの温度測定を行った位置を示した図である。図１において、符号ＨはコンピュータのＣＰＵ等の発熱体を示しており、符号Ｆは放熱構造体１０の放熱体１２に取り付けられた放熱ファンを示している。
また、図１に示すように、本発明の放熱構造体１０は、発熱体Ｈが設置されている部材、例えば、ＣＰＵであれば基盤に対して、クランプ等の固定部材Ｓによって固定される。すると、伝熱シート１１および樹脂フィルム１３は、発熱体Ｈと放熱体１２に挟まれた状態で加圧される。 Below, the usage method of the thermal radiation structure 10 of this invention is demonstrated.
FIG. 1A is a view showing an example of a usage state of the heat dissipation structure 10 of the present invention, and FIG. 1B is a temperature measurement of the heat transfer sheet used for the heat dissipation structure of the present invention in the examples. It is the figure which showed the position. In FIG. 1, symbol H indicates a heating element such as a CPU of a computer, and symbol F indicates a heat dissipating fan attached to the heat dissipating member 12 of the heat dissipating structure 10 .
Further, as shown in FIG. 1, heat dissipation structure 10 of the present invention, the members heating element H is installed, for example, with respect to the base if CPU, solid by the fixing member S such as a clamp Determined. Then, the heat transfer sheet 11 and the resin film 13 are pressurized while being sandwiched between the heat generator H and the heat radiator 12 .

本発明の放熱構造体１０に使用する伝熱シート１１は、かさ密度が1.0Ｍｇ/ｍ３よりも小さいため、発熱体Ｈと放熱体１２に挟まれた状態で加圧されることによって圧縮される。すると、伝熱シート１１はその厚さが薄くなるが、厚さが薄くなるにつれ、伝熱シート１１と、発熱体Ｈや放熱体１２との密着性が向上する。その理由は、伝熱シート１１のかさ密度が小さく、伝熱シート１１を構成する膨張黒鉛同士の間に空間を有しているため、圧縮される過程において、伝熱シート１１の表面に位置する膨張黒鉛が、発熱体Ｈの表面や放熱体１２の表面に存在する凹凸内に侵入するからである。
すると、発熱体Ｈと伝熱シート１１との間の熱抵抗や、伝熱シート１とヒートシンク２との間の熱抵抗が小さくなる。そして、伝熱シート１１は、かさ密度が1.0Ｍｇ/ｍ３よりも小さく、しかも、厚さ方向の熱伝導率が５Ｗ／（ｍ・Ｋ）程度は確保できている。そして、樹脂フィルム１３も厚さ方向の熱伝導率が伝熱シート１と同程度であるから、発熱体Ｈから放熱体１２までの熱抵抗を小さくすることができ、伝熱性が向上する。
よって、放熱構造体１０による、発熱体Ｈを冷却する効率を高くすることができる。 Since the heat transfer sheet 11 used in the heat dissipation structure 10 of the present invention has a bulk density smaller than 1.0 Mg / m 3 , the heat transfer sheet 11 is compressed by being pressed between the heat generation element H and the heat dissipation element 12. The Then, the thickness of the heat transfer sheet 11 is reduced, but as the thickness is reduced, the adhesion between the heat transfer sheet 11 and the heating element H or the heat dissipation body 12 is improved. The reason is that the bulk density of the heat transfer sheet 11 is small and there is a space between the expanded graphites constituting the heat transfer sheet 11 , so that it is located on the surface of the heat transfer sheet 11 in the process of being compressed. This is because the expanded graphite penetrates into the irregularities existing on the surface of the heating element H and the surface of the heat radiating body 12 .
Then, the thermal resistance and between the heating element H and the heat transfer sheet 11, the thermal resistance between the heat transfer sheet 1 and the heat sink 2 becomes small fence. The heat transfer sheet 11 has a bulk density smaller than 1.0 Mg / m 3 , and a thermal conductivity in the thickness direction of about 5 W / (m · K) can be secured. And since the heat conductivity of the thickness direction of the resin film 13 is also comparable to the heat transfer sheet 1, the heat resistance from the heat generating body H to the heat radiating body 12 can be made small, and heat transfer property improves.
Therefore, the efficiency of cooling the heating element H by the heat dissipation structure 10 can be increased.

しかも、伝熱シート１１は、面方向の熱伝導率が５０〜200Ｗ／（ｍ・Ｋ）程度であり、厚さ方向の熱伝導率よりも大きくなっているから、伝熱シート１１の面方向における温度分布をほぼ均一に保つことができる。よって、伝熱シート１１や発熱体Ｈ、放熱体１２にヒートスポットが形成されることも防ぐことが可能となる。 Moreover, the heat transfer sheet 11, the surface direction of the heat conductivity is the 50~200W / (m · K) or so, because larger than the thermal conductivity in the thickness direction, the surface direction of the heat transfer sheet 11 The temperature distribution in can be kept almost uniform. Therefore, it is possible to prevent heat spots from being formed on the heat transfer sheet 11 , the heating element H, and the radiator 12 .

そして、伝熱シート１１は発熱体Ｈと放熱体１２との間に挟まれた状態で配置されているだけであるから、伝熱シート１１の交換が必要となった場合、容易に交換することができ、作業性も向上する。
なお、伝熱シート１１を発熱体Ｈと放熱体１２との間に挟まれた状態で配置できるのであれば、伝熱シート１１と放熱体１２が別体になっていなくてもよく、例えば、接着剤等によって伝熱シート１１を放熱体１２に貼り付けておいてもよい。
また、伝熱シート１１と樹脂フィルム１３とを予め取り付けておけば、伝熱シート１１および樹脂フィルム１３を発熱体Ｈと放熱体１２との間に容易に配置することができるので、より好ましい。 And since the heat-transfer sheet | seat 11 is only arrange | positioned in the state pinched | interposed between the heat generating body H and the heat radiating body 12 , when replacement | exchange of the heat-transfer sheet | seat 11 is needed, it replaces | exchanges easily. Workability is also improved.
In addition, if the heat transfer sheet 11 can be disposed in a state of being sandwiched between the heating element H and the heat radiating body 12 , the heat transfer sheet 11 and the heat radiating body 12 may not be separated, for example, The heat transfer sheet 11 may be attached to the radiator 12 with an adhesive or the like.
Further, if the heat transfer sheet 11 and the resin film 13 are attached in advance, it is more preferable because the heat transfer sheet 11 and the resin film 13 can be easily disposed between the heating element H and the heat dissipation body 12.

図１に示すような状態で放熱構造体１０を発熱体Ｈに取り付ける具体的な手順は、以下のようになる。
まず、発熱体Ｈの上に伝熱シート１を載せてから、この伝熱シート１１の上に樹脂フィルム１３を載せて、その上に放熱体１２を載せる。そして、発熱体Ｈが設置されている部材、例えば、ＣＰＵであれば基盤と固定部材Ｓによって、発熱体Ｈ、伝熱シート１１、樹脂フィルム１３、放熱体１２を挟んで固定すれば、放熱構造体１０を発熱体Ｈに取り付けることができる。
また、放熱構造体１０の放熱性能を高めたい場合には、放熱体１２の上面にファンＦを取り付ければよく、伝熱シート１１、樹脂フィルム１３、放熱体１２およびファンＦによって放熱構造体を構成してもよい。
さらに、放熱構造体１０の放熱体１２として、放熱機能と吸熱機能の両方を備えたものに代えて、ファンＦ等のように放熱機能しか有しないもの、また、冷水ジャケットなどのように吸熱機能しか有しないものとしてもよい。 A specific procedure for attaching the heat dissipation structure 10 to the heating element H in the state shown in FIG. 1 is as follows.
First, the heat transfer sheet 1 is placed on the heating element H, then the resin film 13 is placed on the heat transfer sheet 11, and the heat radiator 12 is placed thereon . And if the heat generating body H is installed, for example, in the case of a CPU, the heat generating body H, the heat transfer sheet 11, the resin film 13, and the heat radiating body 12 are fixed by sandwiching the heat generating body H, the heat transfer sheet 11, the resin film 13, and the heat radiating structure. The body 10 can be attached to the heating element H.
The configuration if desired to increase the heat radiation performance of the heat dissipation structure 10 may be attached to the fan F on the upper surface of the radiator 12, the heat transfer sheet 11, the resin film 13, the heat dissipation structure by heat radiator 12 and the fan F May be.
Further, the heat dissipating body 12 of the heat dissipating structure 10 is replaced with one having both a heat dissipating function and a heat absorbing function, such as a fan F having only a heat dissipating function, and a heat absorbing function such as a cold water jacket. it may be assumed that only have.

そして、伝熱シート１１を、厚さ方向から34.3ＭＰａの加圧力で初めて加圧圧縮したときにおいて、圧縮率が５０％以上であり、かつ、復元率が５％以上となるように調整しておけば、複数回加圧圧縮されても、圧力が除去されたあとにおけるかさ密度は1.0Ｍｇ/ｍ３より小さい状態に保たれる。すると、複数回使用したあとでも、伝熱シート１１が発熱体Ｈと放熱体１２に挟まれた状態で加圧されたときにおける発熱体Ｈや放熱体１２との密着性が高く保たれるから、複数回使用しても熱抵抗を小さく保っておくことができ、再利用性を向上させることができる。
とくに、厚さ方向から34.3ＭＰａの加圧力で初めて加圧圧縮したときにおける圧縮率が５５％以上であり、かつ、復元率が６％以上となるように調整しておけば、より確実に圧力が除去されたあとにおけるかさ密度を1.0Ｍｇ/ｍ３より小さい状態、例えば、0.9Ｍｇ/ｍ３より小さい状態に保つことができ、再利用性をより一層向上させることができる。 Then, when the heat transfer sheet 11 is compressed and compressed for the first time with a pressing force of 34.3 MPa from the thickness direction, the compression rate is adjusted to 50% or more and the restoration rate is adjusted to 5% or more. In this case, the bulk density after the pressure is removed is kept smaller than 1.0 Mg / m 3 even if the pressure is compressed several times. Then, even after using several times, because the heat transfer sheet 11 is kept high adhesion between the heating element H and the heat radiating body 12 at the time when pressurized in a state sandwiched between the heat radiator 12 and the heating element H The thermal resistance can be kept small even when used multiple times, and the reusability can be improved.
In particular, if the compression rate is 55% or more and the restoration rate is 6% or more when it is first pressurized and compressed with a pressure of 34.3 MPa from the thickness direction, the pressure can be more reliably set. It is possible to keep the bulk density after being removed from a state smaller than 1.0 Mg / m 3 , for example, a state smaller than 0.9 Mg / m 3 , and the reusability can be further improved.

なお、伝熱シート１１を、厚さ方向から34.3ＭＰａの加圧力で初めて加圧圧縮したときにおいて、圧縮率が５０％未満であれば、発熱体Ｈや放熱体１２との密着性が悪くなるため好ましくなく、また、復元率が５％未満であれば、再利用したときにおける発熱体Ｈや放熱体１２との密着性を高く保つことができず、再利用に対応できないので好ましくない。 In addition, when the heat transfer sheet 11 is compressed and compressed for the first time with a pressure of 34.3 MPa from the thickness direction, if the compression ratio is less than 50%, the adhesion to the heating element H and the radiator 12 is deteriorated. Therefore, it is not preferable, and if the restoration rate is less than 5%, it is not preferable because the adhesiveness with the heating element H and the radiator 12 when reused cannot be kept high and cannot be used for reuse.

また、伝熱シート１１のかさ密度が1.0Ｍｇ/ｍ３よりも小さくても、固定部材Ｓによって放熱体１２を発熱体Ｈに固定したときに伝熱シート１１に加わる圧力が大きすぎれば、圧力が除去されたあとにおける伝熱シート１１のかさ密度が1.0Ｍｇ/ｍ３以上になってしまう可能性があり、伝熱シート１１に加わる圧力が2.0ＭＰａを超えると、伝熱シート１１を挟んでいる発熱体Ｈにかかる応力の負荷が大きくなるとともに伝熱シート１１の再利用性が低下してしまう。
したがって、伝熱シート１１に加わる圧力が2.0ＭＰａ以下、好ましくは1.5ＭＰａ以下となるように放熱構造体１０を発熱体Ｈに固定するようにすれば、圧力が除去されたあとにおける伝熱シート１１のかさ密度を1.0Ｍｇ/ｍ３よりも小さいままで保っておくことができるので、伝熱シート１１の再利用性を向上させることができ、発熱体Ｈの損傷を抑えることができる。 Even if the bulk density of the heat transfer sheet 11 is smaller than 1.0 Mg / m 3 , if the pressure applied to the heat transfer sheet 11 when the heat dissipating body 12 is fixed to the heat generating body H by the fixing member S is too high, the bulk density of the heat transfer sheet 11 may become 1.0 Mg / m 3 or more in the later but removed, the pressure applied to the heat transfer sheet 11 is more than 2.0 MPa, across the heat transfer sheet 11 The stress load applied to the heating element H is increased, and the reusability of the heat transfer sheet 11 is reduced.
Therefore, if the heat dissipation structure 10 is fixed to the heating element H so that the pressure applied to the heat transfer sheet 11 is 2.0 MPa or less, preferably 1.5 MPa or less, the heat transfer sheet 11 after the pressure is removed. Since the bulk density can be kept smaller than 1.0 Mg / m 3 , the reusability of the heat transfer sheet 11 can be improved, and damage to the heating element H can be suppressed.

そして、かさ密度が0.9Ｍｇ/ｍ３以下の伝熱シート１１を使用し、かつ、伝熱シート１１に加わる圧力が1.5ＭＰａ以下となるように放熱構造体１０を発熱体Ｈに固定するようにすれば、圧力が除去されたあとにおけるかさ密度を0.9Ｍｇ/ｍ３以下の状態に保つことができ、伝熱シート１１と発熱体Ｈおよび放熱体１２との密着性が向上し、かつ、復元性も維持することができる。よって、伝熱シート１１の再利用性を保持しつつ、伝熱シート１１と、発熱体Ｈおよび放熱体１２との密着性をさらに高くすることができ、熱抵抗を低下させることができる。
とくに、かさ密度が0.8Ｍｇ/ｍ３以下の伝熱シート１１を使用し、かつ、伝熱シート１１に加わる圧力が1.0ＭＰａ以下となるように固定部材Ｓによって放熱構造体１０を発熱体Ｈに固定するようにすれば、圧力が除去されたあとにおけるかさ密度を0.8Ｍｇ/ｍ３以下に状態に保つことができ、伝熱シート１１と発熱体Ｈおよび放熱体１２との密着性をさらに向上することができ、かつ、復元性も維持することができる。 Then, the heat transfer sheet 11 having a bulk density of 0.9 Mg / m 3 or less is used, and the heat dissipation structure 10 is fixed to the heating element H so that the pressure applied to the heat transfer sheet 11 is 1.5 MPa or less. If this is done, the bulk density after the pressure is removed can be kept below 0.9 Mg / m 3 , the adhesion between the heat transfer sheet 11 and the heating element H and the radiator 12 can be improved and restored. Sex can also be maintained. Therefore, while maintaining the reusability of the heat transfer sheet 11, the heat transfer sheet 11, the adhesion between the heating element H and the heat dissipation member 12 can be further increased, it is possible to reduce the thermal resistance.
In particular, the heat transfer sheet 11 having a bulk density of 0.8 Mg / m 3 or less is used, and the heat dissipating structure 10 is changed to the heating element H by the fixing member S so that the pressure applied to the heat transfer sheet 11 is 1.0 MPa or less. If fixed, the bulk density after the pressure is removed can be maintained at 0.8 Mg / m 3 or less, and the adhesion between the heat transfer sheet 11 , the heating element H, and the radiator 12 is further improved. It is possible to maintain the resilience.

なお、伝熱シート１１を、含有する硫黄や鉄分等の不純物の総量が１０ppm以下、とくに、硫黄が１ppm以下となるように処理しておけば、伝熱シート１１を取り付けた部材や装置の劣化をより確実に防ぐことができる。 In addition, if the heat transfer sheet 11 is processed so that the total amount of impurities such as sulfur and iron contained is 10 ppm or less, particularly sulfur is 1 ppm or less, deterioration of the member or apparatus to which the heat transfer sheet 11 is attached. Can be prevented more reliably.

本発明の放熱構造体に使用する伝熱シートを、厚さ方向から34.3ＭＰａの加圧力で加圧圧縮したときにおける圧縮率および復元率を調べた。
測定は、厚さ0.5ｍｍの伝熱シートにおいて、かさ密度を0.1，0.5，0.8，1.0，1.2，1.5，1.8Ｍｇ/ｍ３としたときにおける、かさ密度と圧縮率、復元率の関係を確認した。圧縮率は、加圧圧縮前の厚さに対する加圧圧縮中における厚さの割合で評価し、復元率は、加圧圧縮前の厚さに対する、加圧圧縮後加圧力が除去されたときにおける厚さの割合で評価した。
図２（Ａ）に示すように、かさ密度が大きくなるにつれ、圧縮率が低下し、復元率が高くなることが確認できる。
圧縮率と復元率との関係を確認すると、全体として、圧縮率が大きくなるほど復元率が低下していることが確認できるが、圧縮率が５０％以上となると復元率の変化割合が小さくなり、とくに、圧縮率が５５〜７５％までの間では、圧縮率の変化にかかわらず、復元率がほぼ一定に保たれている。
したがって、伝熱シートを、圧縮率が５０％以下、とくに５５〜７５％までの間となるかさ密度、つまり、伝熱シートのかさ密度1.0Ｍｇ/ｍ３より小さくすれば（図２（Ａ）参照）、圧縮率を高くしつつ、復元率はある一定の範囲に保つことができる考えられる。 The compression rate and the restoration rate when the heat transfer sheet used in the heat dissipation structure of the present invention was compressed and compressed from the thickness direction with a pressure of 34.3 MPa were examined.
Measurements confirmed the relationship between bulk density, compression rate, and recovery rate when the bulk density was 0.1, 0.5, 0.8, 1.0, 1.2, 1.5, and 1.8 Mg / m 3 for a 0.5 mm thick heat transfer sheet. did. The compression ratio is evaluated by the ratio of the thickness during the pressure compression to the thickness before the pressure compression, and the restoration ratio is obtained when the applied pressure after the pressure compression is removed with respect to the thickness before the pressure compression. Evaluation was based on the ratio of thickness.
As shown in FIG. 2A, it can be confirmed that as the bulk density increases, the compression rate decreases and the restoration rate increases.
By confirming the relationship between the compression rate and the restoration rate, as a whole, it can be confirmed that the restoration rate decreases as the compression rate increases, but when the compression rate becomes 50% or more, the rate of change in the restoration rate decreases, In particular, when the compression rate is between 55 and 75%, the restoration rate is kept almost constant regardless of the change in the compression rate.
Therefore, if the heat transfer sheet is made smaller than the bulk density at which the compression ratio is 50% or less, particularly 55 to 75%, that is, the bulk density of the heat transfer sheet is 1.0 Mg / m 3 (FIG. 2A). It is considered that the restoration rate can be kept within a certain range while increasing the compression rate.

本発明の放熱構造体に使用する伝熱シートの伝熱性と加圧力との関係を確認するために、伝熱シートを、ＣＰＵ（Intel社製CeleronProssessor ２GHｚ）とヒートシンク（Intel社製Celeron用純正品、アルミニウム製）との間に挟んだ状態において、ＣＰＵによって情報処理量（発熱量）を一定とし運転させた場合におけるＣＰＵ内部温度とヒートシンクの温度の温度差を測定した。
図１（Ｂ）に示すように、ＣＰＵ内部温度と、ヒートシンクにおける温度は２０ｍｍ離れた位置において測定した。
測定に使用した伝熱シートは、かさ密度が、0.1，0.5，0.8，1.0Ｍｇ/ｍ３厚さ0.5ｍｍのものであり、各かさ密度の伝熱シートにおいて、加わる加圧力（ＣＰＵにヒートシンクを取り付ける圧力）を、0.1，0.5，1.0，2.0，5.0ＭＰａと変化させて、温度差の変化を調べた。
なお、温度差が小さいほど伝熱シートの伝熱性が良い、言い換えれば、熱抵抗が小さいことを意味しており、温度差が大きいほど伝熱シートの伝熱性が悪い、言い換えれば、熱抵抗が大きいことを意味している。 To confirm the relationship between the heat conductivity and the pressure of the heat transfer sheet used for heat dissipation structure of the present invention, the heat transfer sheet, CPU (Intel Corp. CeleronProssessor 2GHz) and heat sink (Intel Corp. Celeron for genuine The temperature difference between the CPU internal temperature and the heat sink temperature was measured when the CPU was operated with a constant information processing amount (heat generation amount).
As shown in FIG. 1B, the CPU internal temperature and the heat sink temperature were measured at positions 20 mm apart.
The heat transfer sheet used for the measurement has a bulk density of 0.1, 0.5, 0.8, 1.0 Mg / m 3 and a thickness of 0.5 mm. The pressure difference) was changed to 0.1, 0.5, 1.0, 2.0, and 5.0 MPa, and the change in temperature difference was examined.
Note that the smaller the temperature difference, the better the heat transfer property of the heat transfer sheet, in other words, the smaller the heat resistance, and the greater the temperature difference, the worse the heat transfer property of the heat transfer sheet, in other words, the heat resistance. It means big.

図３に示すように、どのかさ密度においても、加圧力が大きくなるほど温度差が小さくなる傾向を有しており、また、ある一定の加圧力以上になると温度差がほぼ一定になることが確認できる。つまり、温度差がほぼ一定となる加圧力以上に加圧力を強くしても、温度差を小さくできないことが確認できる。
そして、温度差がほぼ一定となる加圧力は、かさ密度が小さくなるほど低くなっており、2.0ＭＰａ以上であれば、すべてのかさ密度において温度差がほぼ一定となることが確認できる。
そして、かさ密度が0.8Ｍｇ/ｍ３以下の場合、加圧力1.0ＭＰａ以上、とくに、1.5ＭＰａ以上とすれば、すべて温度差がほぼ一定とすることができると考えられる。 As shown in FIG. 3, at any bulk density, the temperature difference tends to decrease as the applied pressure increases, and it is confirmed that the temperature difference becomes substantially constant when the applied pressure exceeds a certain value. it can. That is, it can be confirmed that the temperature difference cannot be reduced even if the pressing force is increased beyond the pressing force at which the temperature difference becomes substantially constant.
The applied pressure at which the temperature difference becomes substantially constant decreases as the bulk density decreases. If the pressure is 2.0 MPa or more, it can be confirmed that the temperature difference is substantially constant at all bulk densities.
When the bulk density is 0.8 Mg / m 3 or less, it is considered that the temperature difference can be made almost constant if the applied pressure is 1.0 MPa or more, particularly 1.5 MPa or more.

加圧力を一定にした場合において、本発明の放熱構造体に使用する伝熱シートのかさ密度と伝熱性との関係を確認した。伝熱性の評価は、ＣＰＵ内部温度と、ヒートシンクにおける温度を２０ｍｍ離れた位置において測定し（図１（Ｂ）参照）、実施例２と同様に、その温度差によって評価した。
測定は、厚さ0.5ｍｍの伝熱シートをＣＰＵとヒートシンクとの間に挟み、伝熱シートに対して1.0ＭＰａの加圧力が加わるように取り付けた場合において、伝熱シートのかさ密度を、0.1，0.5，0.8，1.0，1.2，1.8，2.0Ｍｇ/ｍ３としときにおける温度差を測定した。 When the applied pressure was made constant, the relationship between the bulk density and the heat transfer property of the heat transfer sheet used in the heat dissipation structure of the present invention was confirmed. In the evaluation of heat transfer, the CPU internal temperature and the temperature in the heat sink were measured at a position 20 mm away (see FIG. 1B), and the temperature difference was evaluated in the same manner as in Example 2.
In the measurement, when the heat transfer sheet having a thickness of 0.5 mm is sandwiched between the CPU and the heat sink and the pressure is applied to the heat transfer sheet at 1.0 MPa, the bulk density of the heat transfer sheet is set to 0.1 , 0.5, 0.8, 1.0, 1.2, 1.8, 2.0 Mg / m 3 , the temperature difference was measured.

図４（Ａ）に示すように、伝熱シートのかさ密度が上昇しても、かさ密度が0.8Ｍｇ/ｍ３となるまでは温度差はそれほど変化せず、かさ密度が0.8Ｍｇ/ｍ３から1.0Ｍｇ/ｍ３に変化するときに、急激に温度差が大きくなっている。つまり、加圧力を1.0ＭＰａ程度とすれば、かさ密度が0.8Ｍｇ/ｍ３から1.0Ｍｇ/ｍ３の間で熱伝導の効率が急激に変化していることが確認できる。
なお、実施例２の結果と比較すれば、加圧力が1.0ＭＰａから小さくなれば、上記の熱効率が急激に変化するかさ密度も小さくなることが予想できる一方、加圧力が1.0ＭＰａより大きくなっても熱効率が急激に変化するかさ密度はそれほど変化しないと考えらえれる。 Figure 4 (A), the even increased bulk density of the heat transfer sheet, without too much change the temperature difference until the bulk density is 0.8 mg / m 3, a bulk density of 0.8 mg / m 3 When changing from 1.0 to 1.0 Mg / m 3 , the temperature difference suddenly increases. That is, when the applied pressure is about 1.0 MPa, it can be confirmed that the efficiency of heat conduction changes abruptly when the bulk density is between 0.8 Mg / m 3 and 1.0 Mg / m 3 .
In addition, when compared with the result of Example 2, if the applied pressure is reduced from 1.0 MPa, it can be expected that the bulk density at which the thermal efficiency changes rapidly will be reduced, while the applied pressure is greater than 1.0 MPa. However, it can be considered that the bulk density at which the thermal efficiency changes rapidly does not change so much.

加圧力を一定にした場合において、本発明の放熱構造体に使用する伝熱シートのかさ密度と伝熱性との関係が、加圧する回数によって変化するか否かを確認した。伝熱性の評価は、ＣＰＵ内部温度と、ヒートシンクにおける温度を２０ｍｍ離れた位置において測定し（図１（Ｂ）参照）、実施例２と同様に、その温度差によって評価した。
測定は、厚さ0.5ｍｍ、かさ密度0.1，0.5，0.8，1.0Ｍｇ/ｍ３の伝熱シートを、ＣＰＵとヒートシンクとの間に挟んだのち取り外すことを４回繰り返し、各回ににおける温度差を測定した。
図４（Ｂ）に示すように、かさ密度にかかわらず、温度差は毎回ほぼ同じ値を示していることが確認できる。つまり、伝熱シートの伝熱性は、最初にＣＰＵとヒートシンクとの間に取り付ける前のかさ密度、および、ＣＰＵとヒートシンクとの間に取り付けたときにおける加圧力によって影響されることが確認できる。 It was confirmed whether or not the relationship between the bulk density and the heat transfer property of the heat transfer sheet used in the heat dissipation structure of the present invention changes depending on the number of times of pressurization when the applied pressure is constant. In the evaluation of heat transfer, the CPU internal temperature and the temperature in the heat sink were measured at a position 20 mm away (see FIG. 1B), and the temperature difference was evaluated in the same manner as in Example 2.
Measurement is repeated 4 times by removing the heat transfer sheet with thickness 0.5mm, bulk density 0.1, 0.5, 0.8, 1.0Mg / m 3 between the CPU and heat sink, and the temperature difference at each time is measured. It was measured.
As shown in FIG. 4B, it can be confirmed that the temperature difference shows almost the same value every time regardless of the bulk density. That is, it can be confirmed that the heat transfer property of the heat transfer sheet is influenced by the bulk density before first being attached between the CPU and the heat sink, and the applied pressure when being attached between the CPU and the heat sink.

本発明の放熱構造体は、コンピュータや携帯電話などのＣＰＵや、ＤＶＤレコーダー等から発生する熱を放熱する部材として適している。 The heat dissipation structure of the present invention is suitable as a member that dissipates heat generated from a CPU such as a computer or a mobile phone, a DVD recorder, or the like.

（Ａ）は本発明の放熱構造体１０の使用状態の一例を示した図であり、（Ｂ）は実施例において本発明の放熱構造体に使用する伝熱シートの温度測定を行った位置を示した図である。(A) is the figure which showed an example of the use condition of the thermal radiation structure 10 of this invention, (B) is the position which measured the temperature of the heat-transfer sheet | seat used for the thermal radiation structure of this invention in an Example. FIG. （Ａ）は本発明の放熱構造体に使用する伝熱シートにおいて、厚さ方向から34.3ＭＰａの加圧力で加圧圧縮したときにおける圧縮率および復元率とかさ密度の関係を示した図であり、（Ｂ）は圧縮率および復元率の関係を示した図である。(A) is the figure which showed the relationship between the compression rate and the restoration rate, and the bulk density when the heat transfer sheet used for the heat dissipation structure of the present invention is pressurized and compressed with a pressing force of 34.3 MPa from the thickness direction. (B) is the figure which showed the relationship between a compression rate and a decompression | restoration rate. 本発明の放熱構造体に使用する伝熱シートの伝熱性と加圧力との関係を、かさ密度ごとに示した図である。It is the figure which showed the relationship between the heat-transfer property of the heat-transfer sheet | seat used for the heat radiating structure of this invention, and applied pressure for every bulk density. 本発明の放熱構造体に使用する伝熱シートに一定の加圧力を加えた場合において、（Ａ）はかさ密度と伝熱性との関係を示した図であり、（Ｂ）は加圧する回数と伝熱性との関係を示した図である。In the case where a constant pressure is applied to the heat transfer sheet used in the heat dissipation structure of the present invention, (A) is a diagram showing the relationship between bulk density and heat transfer, and (B) is the number of pressurizations. It is the figure which showed the relationship with heat conductivity.

符号の説明Explanation of symbols

１０ 放熱構造体
１１ 伝熱シート
１２ 放熱体
１３ 樹脂フィルム
Ｈ 発熱体
 10 Heat dissipation structure
11 Heat transfer sheet
12 radiator
13 Resin film H Heating element

Claims (5)

発熱体に取り付けられ、該発熱体の熱を放熱する放熱構造体であって、
放熱体と、
該放熱体と前記発熱体との間に配設される膨張黒鉛を素材とする伝熱シートと、
該伝熱シートと前記発熱体との間、もしくは該伝熱シートと前記放熱体との間の、すくなくとも一方に配設される樹脂フィルムとからなる
ことを特徴とする放熱構造体。 A heat dissipating structure that is attached to a heat generator and dissipates heat from the heat generator,
A radiator,
A heat transfer sheet made of expanded graphite disposed between the heat dissipator and the heating element ;
A heat dissipating structure comprising a resin film disposed between at least one of the heat transfer sheet and the heat generating body, or between the heat transfer sheet and the heat dissipating body. . 前記樹脂フィルムは、ポリエチレンテレフタラートである  The resin film is polyethylene terephthalate
ことを特徴とする請求項１記載の放熱構造体。The heat dissipating structure according to claim 1. 前記樹脂フィルムが、前記伝熱シートに取り付けられている  The resin film is attached to the heat transfer sheet
ことを特徴とする請求項１または２記載の放熱構造体。The heat-dissipating structure according to claim 1 or 2. 前記伝熱シートは、かさ密度が、0.8Ｍｇ／ｍ３より小さい
ことを特徴とする請求項１、２または３記載の放熱構造体。 4. The heat dissipation structure according to claim 1 , wherein the heat transfer sheet has a bulk density smaller than 0.8 Mg / m 3 . 前記伝熱シートは、
厚さ方向から34.3ＭＰａの加圧力で加圧圧縮したときにおいて、
圧縮率が５０％以上であり、かつ復元率が５％以上である
ことを特徴とする請求項１、２、３または４記載の放熱構造体。 The heat transfer sheet is
When pressurizing and compressing with a pressing force of 34.3 MPa from the thickness direction,
The heat dissipation structure according to claim 1, 2, 3, or 4 , wherein the compression rate is 50% or more and the restoration rate is 5% or more.
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EP1865552A4 (en) 2008-07-02
TW200638018A (en) 2006-11-01
KR101068416B1 (en) 2011-09-29
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EP1865552A1 (en) 2007-12-12
JP2006286684A (en) 2006-10-19
JP4299261B2 (en) 2009-07-22
WO2006112211A1 (en) 2006-10-26
JP5114255B2 (en) 2013-01-09
NO20075425L (en) 2007-10-25
US20090301697A1 (en) 2009-12-10
EP1865552B1 (en) 2022-06-15
KR20100017859A (en) 2010-02-16

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